1. Field of the Invention
The present invention relates to an automated sewing device for automatically sewing an end of one material with an end of another material into a proper three-dimensional configuration of trim cover assembly that can be used for an automotive seat, a headrest and an armrest, wherein either of the two ends of those two materials includes a rectilinear and/or curved end portion.
2. Description of Prior Art
In general, a process for forming a three-dimensional trim cover assembly adapted to cover the outer surfaces of article for automobile, such as a seat, headrest and armrest, involves the sewing steps of sewing together two end portions respectively of two different shapes of cover base materials (e.g. cloth materials) by use of a sewing machine.
The end of each two different base materials includes a curved end portion, and therefore, it is difficult for a worker to precisely sew together the curved end portions because the worker should move the two base materials with his or her hands, using a long-experienced skill. Such time-consuming and troublesome manual steps has made the sewing process slow and inefficient. The same goes for the case where a rectilinear end of long tape of synthetic resin material is sewn with a curved end of a cloth base material.
To solve such problem, there has been known an automated sewing device for automatically sewing together the curved end portions of plural base materials. For example, the U.S. Pat. No. 5,544,602 (the corresponding Japanese Laid-Open Patent Publication No. 7-194870) discloses an automated sewing device comprising: a table having predetermined patterns of guide grooves formed therein; a guide plate having three guide rollers movably fitted in such guide grooves; a sewing machine; and an auxiliary feeding mechanism. According thereto, a first base material having a curved end portion, which is stored in the auxiliary feeding mechanism, is fed toward the sewing machine, while simultaneously, a second base material having a curved end portion, which is placed on the guide plate, is displaced at a proper angle towards a sewing point under the sewing machine, so that both two curved ends respectively of the first and second base materials are automatically sewn together at that sewing point.
However, the foregoing conventional automated sewing device has been found defective in that the structure thereof is quite complicated with high costs for assembly, and that it takes a lot of time to set the base materials in the corresponding guide plate and auxiliary feeding mechanism. Further, when each base material to be sewn together vary in shape, it is necessary to replace the table by another new one having suited patterns of guide grooves for sewing purpose. Furthermore, the arrangement of guide grooves and guide rollers makes it impossible to quickly and precisely sew together very small curved portions of the base materials.
In view of the above-stated drawbacks, it is a primary purpose of the present invention to provide an improvised automated sewing device which is simplified in structure and allows curved end portion(s) of the two base materials to be sewn together without requiring any other special element, regardless of whether the curved end portion is large or small in curvature.
In order to accomplish such purpose, the automated sewing device in accordance with the present invention is basically comprised of:
a table;
a sewing machine provided on the table, the sewing machine including a sewing needle and a feeding means, which are adapted to feed and sew together first and second base materials in a sewing direction;
the table including a setting area where the first and second materials are to be set in proximity with the sewing needle;
a control means for keeping both first and second end portions respectively of the first and second base materials in alignment with each other and supplying the thus-aligned first and second end portions toward the sewing machine, thereby causing the first and second base materials to be sewn together by the sewing machine along an outer contour of the aligned first and second end portions, with a seam created in the first and second base materials, so that a constant margin is given between the seam and outer contour, the control means including:
a control unit;
a sensor means electrically connected with the control unit, the sensor means being adapted to detect dislocation of either of the first and second end portions, such that, upon detecting such dislocation, the sensor means sends a detection signal to the control unit; and
a guide roller mechanism for guiding either of the first and second base materials in a direction orthogonal with the sewing direction in which the first and second base materials are sewn together by the sewing machine, the guide roller mechanism being electrically connected with the sensor means and including:
a guide means for separating the first base material from the second base material and guiding each of the first and second materials along the sewing direction;
a guide roller means;
a rotation drive means for causing rotation of the guide roller means; and
a transfer means for transferring the guide roller means toward and away from the setting area of table,
with such an arrangement that, responsive to a signal sent from the control unit which has received the detection signal, the guide roller mechanism is operated such that the transfer means works to transfer the guide roller means toward and away from the setting area, while at the same time, the rotation drive means works to cause rotation of the guide roller means in one of normal and reverse directions so as to cause displacement of either of the first and second base materials in the direction orthogonal with the sewing direction, whereby either of the first and second end portions is returned to a fixed point in said sensor means, whereby both first and second base materials are sewn together along the respective end portions thereof, with the constant margin given between the seam and the outer contours of the first and second end portions.
In one aspect of the present invention, the guide means may comprise a guide element extending toward the sewing needle of sewing machine, the guide element having a body of generally inverted-U-shaped cross-section and a through-hole defined therein, thereby allowing the first base material to be guided in and along the through-hole in the sewing direction, while allowing the second base material to be guided upon the body of the guide element in the sewing direction.
In another aspect of the present invention, the sensor means may comprise: a first sensor means adapted to detect dislocation of the first end portion of first base member; and a second sensor means adapted to defect dislocation of the second end portion of second base member. The guide means may be provided at the setting area on the table in proximity to the sewing needle, wherein the guide means includes a plate element having an upper surface defined above the table so that a space is defined between the upper surface and the table, thereby allowing the first base material to be guided within the space in the sewing direction, while allowing the second base material to be guided upon the upper surface of the plate element in the sewing direction. The first sensor means may be provided in the space, and the second sensor means be provided on the upper surface of the plate element. The rotation drive means may comprise: a first rotation motor connected with the first guide roller; and a second rotation motor connected with the second guide roller. The transfer means may comprise a first cylinder connected with the first rotation motor and a second cylinder connected with the second rotation motor. A hole may be formed in the table at the setting area in vicinity of the sewing needle. The first guide roller be disposed under said table and below said hole, and the second guide roller be disposed above the plate element.
Other various features and advantages will become apparent from reading of the descriptions hereinafter, with reference to the appended claims.